The 11th annual report from the American Council for an Energy-Efficient Economy (ACEEE) shows which states are doing the best on energy efficiency — a critical tool for withstanding and recovering from storms and economic shocks. Massachusetts broke its 2016 tie with California by holding on to the No. 1 ranking, while the Golden State slipped to No. 2. As national leaders, Rhode Island, Vermont, and Oregon round out the top five in the ACEEE Scorecard. Idaho posted the most gains by far in 2017, surging past a number of mid-ranked states in ACEEE’s comparative index of efficiency policies, best practices, and other metrics. Idaho advanced seven spots, from 33rd to 26th place. The balance of the 10 most-improved states are Virginia, Oklahoma, Florida, Utah, Nevada, Louisiana, Oregon, Washington, D.C., and Kentucky.